5: Expirimental Research Flashcards
Expiriment
A type of study designed specifically to answer the question of whether there is a causal relationship between two variables.
- researchers manipulate, or systematically vary, the level of the independent variable (or, conditions)
- researcher exerts control over, or minimizes the variability in, variables other than the independent and dependent variable (extraneous variables)
Conditions
The different levels of the independent variable to which participants are assigned.
Control
Holding extraneous variables constant in order to separate the effect of the independent variable from the effect of the extraneous variables.
Manipulate
Changing the level, or condition, of the independent variable systematically so that different groups of participants are exposed to different levels of that variable, or the same group of participants is exposed to different levels at different times.
Single Factor Two-Level Design
An experiment design involving a single independent variable with two conditions.
Single Factor Multi-Level Design
When an experiment has one independent variable that is manipulated to produce more than two conditions.
Confounding Variable
An extraneous variable that varies systematically with the independent variable, and thus confuses the effect of the independent variable with the effect of the extraneous one.
- can be limited by holding extraneous variables constant
Treatment
Any intervention meant to change people’s behavior for the better.
Treatment Condition
The condition in which participants receive the treatment.
Control Condition
The condition in which participants do not receive the treatment.
Randomized Clinical Trial
An experiment that researches the effectiveness of psychotherapies and medical treatments.
No-Treatment Control Condition
The condition in which participants receive no treatment whatsoever.
Placebo
A simulated treatment that lacks any active ingredient or element that is hypothesized to make the treatment effective, but is otherwise identical to the treatment.
Placebo Effect
An effect that is due to the placebo rather than the treatment.
Waitlist Control Condition
Condition in which participants are told that they will receive the treatment but must wait until the participants in the treatment condition have already received it.
- potential solution to the placebo issue
Between-Subjects Expiriment
An experiment in which each participant is tested in only one condition.
advantages:
- being conceptually simpler and requiring less testing time per participant
- avoid carryover effects without the need for counterbalancing
Within-Subjects Expiriment
An experiment in which each participant is tested under all conditions.
advantages:
- controlling extraneous participant variables, which generally reduces noise in the data and makes it easier to detect any effect of the independent variable upon the dependent variable
- require fewer participants than between-subjects experiments to detect an effect of the same size
Random Assignment
Means using a random process to decide which participants are tested in which conditions.
Block Randomization
All the conditions occur once in the sequence before any of them is repeated.
Matched-Groups Design
An experiment design in which the participants in the various conditions are matched on the dependent variable or on some extraneous variable(s) prior the manipulation of the independent variable.
Order Effect
An effect that occurs when participants’ responses in the various conditions are affected by the order of conditions to which they were exposed
- primary disadvantage of within-subjects designs
Carryover Effect
An effect of being tested in one condition on participants’ behavior in later conditions.
- includes practice effect, fatigue effect
Practice Effect
An effect where participants perform a task better in later conditions because they have had a chance to practice it.
Fatigue Effect
An effect where participants perform a task worse in later conditions because they become tired or bored.
